We spend so much time commuting that romance is regularly sparked by glances across overcrowded railway carriages – a tribute to the indomitable spirit of St Valentine.

While in most countries the national operator is happy to let love take its own course, Dutch rail company NS has decided to teach passengers how to make the most of the opportunity for romance.

To prepare commuters for St Valentine’s Day, NS is offering free expert coaching in the secrets of successful flirtation in a special carriage on board its trains from Amsterdam to Maastricht today.

They have recruited lifestyle coach Esther Popelier to show passengers how to make eye contact and how to capitalise on that initial contact to get chatting and perhaps arrange a more intimate rendezvous.

Crowded trains are the ideal place to practise the delicate art of flirting, says Ms Popelier. “If you can make a personal connection in such an everyday environment, that’s great. And if not, it doesn’t really matter.”

NS says its own research shows that 3 per cent of commuters have had a romance with a fellow passenger – which, says NS, is good, but not good enough.

“The biggest problem is that when two people make eye contact they are often too embarrassed to speak to one another,” says Ms Popelier. “That’s the barrier that has to be broken if you want to get to know someone – and getting to know people is fun.”